Integrated assembly for delivery of air stream for optical analysis

ABSTRACT

An integrated particle detection apparatus for optical detection of particles in an air stream. The particle detection apparatus includes a scalper for removing large panicles from the air stream, a concentrator for separating out small particles and increasing the concentration of particles of interest, and a fluorescence sensor system for detecting the particles present in the air stream. The scalper, concentrator and sensor comprise a single integrated unit, such that the scalper is fluidly contiguous with the concentrator and the concentrator is fluidly contiguous with the sensor.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Work on this invention was carried out under Defense Advanced ResearchProjects Agency (“DARPA”) Microsystems Technology Office contract No.N66001-02-C-8016 in support of a program entitled SemiconductorUltraviolet Optical Sources (“SUVOS”). The government has certain rightsin the invention.

TECHNICAL FIELD

This invention relates to particle detection systems and, in particular,to pre-filter, concentrator and sensor assemblies for providing samplepreparation and delivery for optical particle detection.

BACKGROUND OF THE INVENTION

Contamination control, including particulate monitoring, plays a role inthe manufacturing processes of several industries. These industriesrequire clean rooms or clean zones with active air filtration andrequire the supply of clean raw materials such as process gases,de-ionized water, chemicals, and substrates. In the pharmaceuticalindustry, the Food and Drug Administration requires particulatemonitoring because of the correlation between detected particles in anaseptic environment and viable particles that contaminate the productproduced.

Recent attention has been given to the monitoring and detection ofbiological agents. If aerosolized agents (biological particles) areintroduced into an environment and are within the respirable range ofparticle sizes, then the biological particles may deposit in human lungsresulting in illness or death.

Biological contamination can occur not only in open air, but also inconfined spaces, such as postal handling equipment, aircraft, hospitals,water supplies, and air ducts. Minimizing the introduction of biologicalparticles in an environment requires the fast detection of pathogens.Laser-induced fluorescence (“LIF”) of fluorescent biological substances(biofluorophores) provides a real-time technique for identifying thepotential presence of airborne pathogens such as aerosolized bacterialspores and viruses. Biofluorophores significant to LIF include, but arenot limited to, tryptophan, NADH, and riboflavin or other flavinoids.

Assemblies that have been used in the detection of particles includepre-filter scalpers, concentrators and LIF sensors. The scalper andconcentrator may be used to separate out undesirable particles andsupply the air stream sample to an LIF sensor in a manner conducive toLIF detection. A scalper in this context may be a device used toseparate out particles in the sample air stream, for example, based onparticle size. A scalper may be used to remove large particles from thesample air stream. A concentrator may be used to increase particleconcentration by increasing the number of particles by volume in thesample air stream.

Traditional implementations of LIF sensor systems use a separate scalperand a separate concentrator to prepare the sample air stream and provideparticles to the LIF sensor. The separate scalper, concentrator andsensor assemblies were often bulky, which can be a disadvantage. Forexample, the allowable space for the detection system may be limitedwhen the sample air stream is in an environment such as air ducts.Furthermore, tubing is required to interconnect the scalper and theconcentrator with the LIF sensor. Tubing has a tendency to trapparticles of interest, which frequently results in fewer particlesentering the sensor.

Furthermore, in traditional LIF sensors, the sample sensor compartmentwhere the sample stream and the incident excitation beam meet is oftendifficult to access. Typically, the only way to clean the sample sensorcompartment is by accessing it through the various module ports,resulting in poor access to the interior surfaces that require cleaning.Furthermore, to access the interior sample sensor compartment throughthe ports requires the removal of either the laser module, the elasticscatter device, the photodetector device or the dispersive fluorescencedetector device.

Therefore, it would be an advancement in the art to address one or moreof these problems. It would also be desirable to provide an apparatusthat is less bulky than previous implementations.

SUMMARY OF THE INVENTION

The embodiments disclosed have been developed in response to the presentstate of the art, and in particular, in response to the problems andneeds in the art that have not yet been fully solved by currentlyavailable particle detection systems. According to one embodiment, anintegrated air stream delivery apparatus suitable for use with a systemfor performing analysis based on optical illumination of a sample airstream is provided. The delivery apparatus has a scalper portion, aconcentrator portion and an illumination area that make up a singleintegrated unit and are also in fluid communication with each other.

The scalper portion can separate particles within the air stream basedon particle size. The concentrator portion can alter the concentrationof particles that are within the sample air stream. The illuminationarea may receive the sample air stream from the concentrator portion.The illumination area may be configured to receive illumination from alight source for illuminating the sample air stream.

The scalper, concentrator and illumination area may be defined by ahousing. The housing may define passageways through which the sampleflows between the scalper portion, concentrator portion and illuminationarea. The apparatus may include a flow manifold where flow passages areintegrated in the housing. The housing may also be made of removablepieces, such as two housing portions, for providing access to theinterior of the scalper portion, concentrator portion and illuminationarea. A sealing member or gasket may also be included to provide a sealwhen the housing portions are joined together.

The apparatus may also include a sample nozzle for delivering the sampleair stream to the illumination area. The position of the sample nozzlewithin the housing may be adjustable from outside the housing. A sheathnozzle may also be machined or otherwise formed in the housing and beconcentric with the sample nozzle.

According to one embodiment, the scalper portion may remove some or allparticles from the sample air stream that are larger than a definedmaximum size limit, such as about 10 microns in diameter. Furthermore,the concentrator portion may increase the concentration, or number ofparticle by volume, within the sample. The concentrator portion may alsoremove from the sample particles that are smaller than a defined minimumsize limit, such as about one micron in diameter.

The illumination area may include a chamber, at least one port forreceiving a light source and at least one port for receiving an opticaldetector. The apparatus may also include at least one optical detector,such as a fluorescence detector. Alternatively or in combination, atleast one optical detector may be an elastic scatter detector, a laserpower detector, and an obscuration detector. The light source may be alaser light source or it could be a light emitting diode.

Additionally a particle detection apparatus for detecting particles in asample air stream is disclosed. The particle detection apparatus mayinclude a scalper, a concentrator and a sensor, wherein the scalper isfluidly contiguous with the concentrator and the concentrator is fluidlycontiguous with the sensor. The concentrator may be configured toincrease the concentration of particles within the sample air stream.The sensor may be configured to detect particles.

The sensor may be an induced fluorescence sensor system. Thefluorescence sensor system may include a light source, a fluorescencedetector, a light source power detector and an elastic scatter detector.The light source may be a laser-light source or alternatively, the lightsource may be a light emitting diode. The light source may be adjustablein all directions along a mounting plane.

According to yet another embodiment, a particle detection apparatus fordetecting particles in a sample air stream may include a scalper, aconcentrator, a sample sensor compartment where fluorescence of sampleparticles occur, and a housing. The scalper, concentrator, and samplesensor compartment may be in fluid communication with each other and aredefined by the housing.

These and other features and advantages of the disclosed embodimentswill become more fully apparent from the following description andappended claims, or may be learned by the practice thereof as set forthhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments will become more fully apparent from thefollowing description and appended claims, taken in conjunction with theaccompanying drawings. Understanding that these drawings depict onlytypical embodiments and are, therefore, not to be considered limiting ofthe invention's scope, the embodiments will be described with additionalspecificity and detail through use of the accompanying drawings inwhich:

FIG. 1 is perspective view of one embodiment of an integrated particledetection apparatus for detecting particles in a sample air streamincluding an LIF sensor system;

FIG. 2 is an exploded perspective view of the integrated particledetection apparatus of FIG. 1 absent some of the LIF sensor components;

FIG. 3 is an exploded perspective view of the integrated particledetection apparatus of FIG. 2 as shown from an alternative angle;

FIG. 4A is a side elevation view of the integrated particle detectionapparatus of FIG. 1 absent some of the LIF sensor components;

FIG. 4B is a cross-sectional side elevation view of the integratedparticle detection apparatus of FIG. 4A as viewed from thecross-sectional plane 4B—4B;

FIG. 4C is an enlarged partially cut-away cross-sectional side view of asample sensor compartment as indicated by region 4C in FIG. 4B;

FIG. 4D is a cross-sectional bottom end view of the of the integratedparticle detection apparatus of FIG. 4A as viewed from thecross-sectional plane 4D—4D;

FIG. 5A is an alternative side elevation view of the integrated particledetection apparatus of FIG. 4A;

FIG. 5B is a cross-sectional side elevation view of the integratedparticle detection apparatus of FIG. 5A as viewed from thecross-sectional plane 5B—5B;

FIG. 5C is an enlarged partially cut-away cross-sectional side view ofthe integrated particle detection apparatus of region 5C in FIG. 5B; and

FIG. 5D is a cross-sectional bottom end view of the integrated detectionapparatus of FIG. 5A as viewed from the cross-sectional plane 5D—5D.

DETAILED DESCRIPTION

It will be readily understood that the components of the embodiments asgenerally described and illustrated in the Figures herein could bearranged and designed in a wide variety of different configurations.Thus, the following more detailed description of various embodiments, asrepresented in the Figures, is not intended to limit the scope of theinvention, as claimed, but is merely representative of the embodimentsof the invention.

The word “exemplary” is used exclusively herein to mean “serving as anexample, instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments. While the various aspects of theembodiments are presented in drawings, the drawings are not necessarilydrawn to scale unless specifically indicated.

The phrases “connected to” and “coupled to” refer to any form ofinteraction between two or more entities, including mechanical,electrical, magnetic, electromagnetic, and thermal interaction. Twocomponents may be coupled to each other even though they are not indirect contact with each other.

The phrase “attached directly to” refers to a form of attachment bywhich the attached items are either in direct contact, or are onlyseparated by a single fastener, adhesive, or other attachment mechanism.The term “abutting” refers to items that are in direct physical contactwith each other, although the items may not necessarily be attachedtogether.

FIG. 1 represents one embodiment of an integrated air stream deliveryapparatus, particularly a particle detection apparatus 110 for detectingparticles in a sample air stream as illustrated from a perspective view.The air stream may be a stream of any appropriate carrier gas. Theparticles may be solid, liquid (such as droplets), or other phases ofmatter or combinations thereof. The apparatus may be used for analysisof the air stream, the particles, or both.

The particle detection apparatus 110 illustrated includes a scalper 112,a concentration-changing portion (“concentrator”) 114, and a sensorsystem 116. The particle detection apparatus 110 is formed from ahousing 118, which may be constructed via an injection molded process.Alternatively, the housing 118 may be machined to provideaerodynamically smooth internal surfaces. Moreover, the housing 118 mayalso be constructed through a die cast process or other constructionprocess known to those having skill in the art. According to oneembodiment, the housing 118 is composed of aluminum. Alternatively, thehousing 118 could be composed of other metals, metal alloys, polymers orother suitable material.

According to the embodiment illustrated in FIG. 1, the housing 118defines the scalper 112, concentrator 114, and a sample sensorcompartment that is disposed within an illumination area or sensor body115. In other words, the scalper 112, the concentrator 114, and samplesensor compartment are formed into the housing so all three comprise anintegrated unit. The sample sensor compartment is where fluorescenceoccurs when the excitation source illuminates the sample air stream,including any particles therein. Consequently, the scalper 112 is not aseparate component, but rather an integrated part of the housing 118,and as such could be referred to as a scalper portion 112. Theconcentrator 114 is also defined by and is an integrated part of thehousing 118, and could be referred to as a concentrator portion 114. Thesensor body 115 is also defined by and is an integrated part of thehousing 118 and could be referred to as the sensor body portion 115.

According to the embodiment illustrated, the sensor system 116 includesa light source 120. The light source 120 may be a laser-light source andthe sensor system 116 may be an LIF sensor system. The laser-lightsource could be a conventional blue, violet, or ultraviolet (“UV”) diodelaser, a frequency-tripled or quadrupled neodymium laser, or otherlaser-light source known to those having skill in the art.Alternatively, the light source 120 may be a light emitting diode(“LED”) or other light source which can be used to illuminate the airstream for appropriate detection.

According to the embodiment illustrated in FIG. 1, the laser-lightsource 120 is a dual diode laser beam combining module. This lasermodule 120 combines two diode laser beams of different wavelengths intoa single beam. The wavelengths generated may be, for example, 375nanometers and 405 nanometers. However the laser module 120 mayaccommodate other wavelengths as desired. The laser module 120 may beencased in a dust and light-tight cover 122. The apparatus 110 may alsoaccommodate single illumination sources, different combined illuminationsources, uncombined multiple illumination sources, or combinationsthereof, which sources may be lasers, light emitting diodes, or othersources.

The LIF sensor system 116 also may include a laser power detector 124 onthe opposite side of the sensor body 115 from the laser module 120. Thelaser power detector 124 may be used for measuring the laser power orenergy leaving the optical train of the laser module 120. The laserpower detector 124 may be used as a relative reference of laser powerfor spectrum normalization so that the laser power fluctuation does notaffect measurement accuracy.

The LIF sensor system 116 also includes a dispersive fluorescencedetector 126, which is typically located normal to the excitation beam.A variety of fluorescence detectors 126 may be used, including, but notlimited to photomultiplier tubes (“PMTs”) in analog or photon-countingmode, diode arrays and charge-transfer detectors. One having skill inthe art would recognize that various forms of transducers may be usedthat provide large amplifier gains to measure low intensity fluorescencesignals.

The illumination area 115 may include ports which receive, or which arein optical communication with optical detectors. Multiple detectors mayalso be used with different filters to measure fluorescence emission atvarying wavelengths. Alternatively, a single detector may be used inwhich all the fluorescence spectral bands share a common aperture andare then dispersed onto a single multiple-pixel detector using adiffraction grating. In the latter system a long-pass filter may beincluded to block stray laser light at the excitation wavelength.

The detectors may also include other types of detectors, for instance,to detect or measure extinction or obscuration of an illuminationsource, or scatter, fluorescence, color, or other optically detectableinformation about the particles and/or air stream. They may include, forinstance, photon counters, photomultipliers, charge-coupled devices, orspectrophotometers. They may also include one or more filters,polarizers, or other devices that affect the properties of the detectedillumination.

The LIF sensor system 116 may also include an elastic scatter detector128. Information from an elastic scatter signal can be used incombination with fluorescence intensity information from thefluorescence detector to develop information that is different from thefluorescence intensity signal alone. For instance, the information fromboth detectors may be used to calculate a fluorescence-to-elasticscatter ratio (F/E) which takes account of particle size. The ratio mayalso be normalized so that it has a finite domain (for instance from −1to +1) instead of an infinite domain (such as 0 to infinity). Elasticscatter information may also help to distinguish interferent particleswith fluorescence properties similar to pathogens, but with differentsize distributions. Elastic scatter information also can gate thecounting of fluorescence photons.

Referring still to FIG. 1, particle-laden air flows into the particledetection apparatus inlet 130 and through the scalper portion 112. Thescalper 112 may remove particles that exceed a maximum size limit, suchas particles that are larger than about 10 microns in diameter.Alternatively, the scalper 112 may be configured to removedifferently-sized particles. The larger particles that are stripped offexit the scalper portion 112 through a scalper's minor exhaust 132.According to the embodiment shown in FIG. 1, the scalper 112 is avirtual impactor that separates particles by size into two air streams.However, alternative scalper devices may be used as known to thosehaving skill in the art, such as a cyclone device.

Flow of the sample air stream continues from the scalper 112 to theconcentrator 114. The concentrator 114 functions to increase the numberof particles within a respirable range (approximately 1 to 10 microns)by volume, i.e., increase particle concentration. However, aconcentrator could also be used to dilute the concentration of particlesin a sample, if desired. The concentrator 114 used in the embodimentshown in FIG. 1 may increase the particle concentration by a factor ofabout ten. The concentrator 114 also separates out particles smallerthan a defined minimum size limit, such as particles smaller than aboutone micron in diameter. The smaller particles exit the particledetection apparatus 110 through a concentrator exhaust 134 along withmuch of the air of the sample stream. Like the scalper 112, theconcentrator 114 illustrated is a virtual impactor. Also like thescalper 112, alternative devices may be used as known to those havingskill in the art, such as a cyclone device.

The remaining particles in the sample air stream, such as those in the 1to 10 micron range (often referred to as the “respirable range”),continue through a sample nozzle (not shown). The particles then flowfrom the sample nozzle into the sample sensor compartment and into aview volume within the sensor body 115, that is part of the LIF sensorsystem 116. The particles are then interrogated by the fluorescenceexcitation beam generated by the laser module 120. After fluorescencedetection occurs, the sample air stream flows out of the integratedparticle detection apparatus 110 through a sensor exhaust (not shown).

FIG. 2 illustrates the integrated particle detection apparatus 110represented in FIG. 1, but from an exploded perspective view. Theparticle detection apparatus 110 depicted in FIG. 2 is illustratedabsent the LIF sensor components such as the laser module, dispersivefluorescence detector, laser power detector, and elastic scatterdetector. Consequently, the particle detection apparatus 110 may also beconsidered a particle delivery apparatus 110 for delivering particles toa location where optical detection of particles may occur.

As shown in FIG. 2, the housing 118 of the particle detection apparatus110 may have a clamshell design forming two portions 140, 142, one ofwhich is fixed and one of which is removable. A fixed portion 140 may beconfigured to be fixedly coupled, or attached directly to a UV-LIFbio-aerosol sensor instrument assembly (which may include, among otherthings, flow meters, a pump, a blower, filters, fans, a power supply,and a printed circuit board stack) or frame thereof. A removable portion142 may be connected to the fixed portion 140, but could be easilyremoved to provide access to the interior of the particle detectionapparatus 110 for cleaning or servicing. This is advantageous overprevious “one-piece” sensor assemblies because the only access tocleaning one-piece sensors is through module ports, resulting in pooraccess to surfaces that should be kept clean.

In the embodiment shown in FIG. 2, the two housing portions 140, 142split the integrated particle detection apparatus 110 approximately inhalf longitudinally and widthwise. Therefore, approximately half of thescalper 112, half of the concentrator 114, and half of the sensor body115 are found on the fixed half 140, while half of the scalper 112, halfof the concentrator 114, and half of the sensor body 115 are formed onthe removable half 142. The term “half” is not intended to mean exactly50% by size or weight. Rather, two halves in this context mean that eachhalf has a similar size as the other half. For example, a laser moduleport 144 may be formed in the fixed half 140, but not the removable half142 so that laser module removal is not necessary when the removablehalf 142 is taken off for cleaning. A laser power detector port 146 alsomay be formed in the fixed half 140 so that the laser power detector(not shown) does not need to be removed when the removable half 142 isremoved. Alternatively, the housing 118 may be formed from a fixedportion 140 and a removable portion 142 which are not similar in size.

FIG. 2 also shows a sample sensor compartment 148 where fluorescenceoccurs when the excitation source interrogates the sample stream. Thesample sensor compartment 148 could also be considered part of theillumination area where the sample particle stream is delivered from theconcentrator 114. Approximately half of the sample sensor compartment148 is located on the fixed half 140 of the particle detection apparatus110, while the other half is located on the removable half 142 of thedetection apparatus 110.

The two halves 140, 142 each have a mating surface 150 which abut eachother when placed in a closed configuration (as shown in FIG. 1). Thetwo halves 140, 142 may be coupled to each other through the use offasteners, such as cap screws 152. Alternative fasteners and fasteningmethods may be used such as clamps, which may speed disassembly of theparticle detection apparatus 110.

Particle-laden air flows into the particle detection apparatus inlet 130and into a scalper chamber 154 of the scalper portion 112. As discussedpreviously, the scalper 112 may remove particles in the air stream thatexceed a maximum size limit, such as particles that are larger thanabout 10 microns. The larger particles that are stripped off exit thescalper 112 through the scalper exhaust 132.

Flow of the sample air stream continues from the scalper 112 to aconcentrator cavity 156 via passageway 158. The concentrator 114separates out particles smaller than a minimum size limit and increasesthe concentration of particles in the respirable range. The smallerparticles exit the particle detection apparatus 110 with a majority ofthe air flow through the concentrator exhaust 134. Alternatively, thescalper 112 may be located downstream of the concentrator 114.

The remaining particles in the sample air stream (e.g., those in the 1to 10 micron range) enter into a sample nozzle 160 through its upper end162. The upper end 162 of the sample nozzle 160 may have a roundcross-section and is machined to provide a smooth transition for theparticle-laden flow as it exits the concentrator 114 and enters thesample nozzle 160. According to one embodiment, the sample nozzle 160 isconstructed from steel tubing. The cross-section of the nozzle 160 isround at its upper end 162 and then transitions to an elliptical or“racetrack”-shaped cross section. The elongated shape of the samplenozzle 160 delivers the sample in a configuration that maximizesfluorescence efficiency due to the shape of the laser beam source. Flowthrough the sample nozzle 160 may be laminar. However, laminar flow isnot required; in alternative embodiments flow to the illumination areaor out of the sample nozzle 160 could be turbulent.

The sample nozzle 160 may be coupled to the fixed half 140 of theparticle detection apparatus 110 through the use of a sample nozzleclamp 164. According to the embodiment illustrated in FIG. 2, the samplenozzle clamp 164 is shaped to pinch the upper end 162 of the samplenozzle 160 without crushing it and/or restricting the particle-ladenflow. The sample nozzle clamp 164 may be tapered around its perimeter toseal it to the removable half 142 of the particle detection apparatus110 when the two halves 140, 142 are in the closed configuration.

The sample nozzle clamp 164 can be loosened through nozzle clamp screws165 and the position of the sample nozzle 160 can be adjusted thereby.The nozzle clamp screws 165 may be accessible even when the two halves140, 142 are in the closed configuration by removing nozzle clamp accessscrews 166 that are exposed on an exterior of the housing 118. Once thenozzle clamp access screws 166 are removed, the nozzle clamp screws 165can then be accessed to loosen or tighten the sample nozzle clamp 164 asdesired. Consequently, the position of the sample nozzle 160 within thehousing 118 may be adjusted by an operator from outside of the housing.

The integrated particle detection apparatus 110 may also include asheath nozzle 168 that is integrated into the housing 118. Previousimplementations of particle detection systems required the use of aseparate formed tube for the sheath nozzle. According to the presentembodiment, the sheath nozzle 168 may be machined into the housing 118concentric with the location of the sample nozzle 160, such that itencompasses the sample nozzle 160. Clean air from the sheath nozzle 168flows around the sample nozzle 160 and helps control the shape of theparticle-laden flow as it exits the sample nozzle 160 at its lower end170. The clean flow from the sheath nozzle 168 also may help preventoptical surfaces from being coated with particles.

Once the particle-laden sample air stream has exited the sample nozzle160 it enters into the sample sensor compartment 148 where the sample isirradiated by the excitation beam and fluorescence detection occurs. Theremovable half 142 of the particle detection apparatus 110 may includean elastic scatter detector port 172 where the elastic scatter detector(not shown) may be coupled to measure elastic scatter duringfluorescence analysis. After fluorescence detection occurs, the sampleair stream flows out of the integrated particle detection apparatus 110through a sensor exhaust 174.

FIG. 3 illustrates the integrated particle detection apparatus 110represented in FIG. 2, but from an alternative angle of an explodedperspective view. FIG. 3 illustrates the interior portion of theremovable half 142 of the particle detection apparatus 110 including theother half of the scalper 112, concentrator 114, sheath nozzle 168 andsample sensor compartment 148.

When in use, the two halves 140, 142 of the particle detection apparatus110 are in the closed configuration (as shown in FIG. 1). In the closedconfiguration the mating surface 150 of the removable half 142 typicallyabuts the mating surface of the fixed half 140. It is desirable for theabutting mating surfaces 150 to form a seal so that the particledetection apparatus 110 can build up air pressure in the interiorcavities. Although it could be, the seal does not necessarily need to behermetic. Rather, the seal may be such that the particle detectionapparatus 110 can build up air pressure in its interior cavities.

The abutting mating surfaces 150 typically do not provide a sufficientseal through bolt pressure alone because of the many features on themating surface 150. Consequently, the mating surface 150 may include asealing member, such as a sealing gasket 180 or O-ring cord that extendsaround the perimeter of the removable half 142. The sealing gasket 180may be pressed or otherwise disposed in a sealing groove 182 thatextends around the perimeter of the removable half. Alternatively, thesealing member 180 may extend around the fixed half 140.

According to the embodiment shown in FIGS. 2 and 3, the mating surface150 of the fixed half 140 is flat and does not have a sealing groove182. The sealing gasket 180 may have a diameter slightly larger than thewidth of the sealing groove 182, such that the sealing gasket 180protrudes slightly out of the groove 182 to form a seal when theremovable half 142 is secured to the fixed half 140. The sealing gasket180 may then remain in the sealing groove 182 when the two halves 140,142 are separated. The sealing groove 182 may be disposed around all thefeatures in the perimeter of the removable half 142, such as the inlet130, concentrator exhaust 134, etc.

Since the mating surfaces 150 of the two halves 140, 142 of the particledetection apparatus 110 typically abut each other, the sealing gasket180 may have a cross-sectional area that is slightly less than thecross-sectional area of the sealing groove 182 so that the sealinggasket 180 can compress in the groove 182 and the two halves 140, 142are not held apart by the sealing gasket 180.

Referring still to FIG. 3, the fixed half 140 has multiple flow manifoldports 184, some of which receive a purge flow orifice 186 or a sheathflow orifice 188. The purge and sheath flow orifices 186, 188 may screwinto threaded features (not shown) on the interior of the flow manifoldto control the sheath and purge flow. Flow manifold plugs 190 may alsobe received by the flow manifold ports 184. Purge and sheath flow willbe discussed in greater detail in conjunction with FIGS. 4A through 5D.

The fixed half 140 of the particle detection apparatus 110 may alsoinclude laser module attachment locations 192 where the laser module (ofFIG. 1) may be coupled to the housing 118. Laser module adjustmentplates 194 may be coupled to the side and base of the housing 118 toallow the laser module (of FIG. 1) to be moved in all directions along amounting plane 196. Alignment of the laser module may be accomplishedusing set screws 198 mounted on the laser module adjustment plates 194.The adjustability of the laser module in all directions along themounting plane 196 may be desirable in the event the sample nozzle 160is adjustable in a vertical direction only.

FIG. 4A illustrates the integrated particle detection apparatus 110 ofFIG. 1 from a side elevation view. As discussed previously, the particledetection apparatus 110 includes the scalper 112, the concentrator 114and the sample sensor body 115. The sample sensor body 115 illustratedin FIGS. 4A through 5D is shown absent its sensor components such as thelaser module and various detectors. The scalper 112, concentrator 114and sensor body 115 form an integrated unit, such that the scalper 112is fluidly contiguous with the concentrator 114, and the concentrator isfluidly contiguous with the sample sensor body 115. This eliminates theneed for air supply tubes and fittings.

Furthermore, the integrated design reduces the number of parts comparedto known designs, which results in lower cost and less complexity asprevious designs. Moreover, integrating flow system components such asorifices (not shown) into the particle detector apparatus 110 alsoreduces system complexity.

Plane 4B—4B extends through the length and depth of the particledetection apparatus 110 and passes through the scalper 112, theconcentrator 114, the sample sensor compartment 148, the sample nozzle160, the sheath nozzle (not shown) and a sheath flow orifice (notshown). Plane 4D—4D extends through the width and depth of the particledetection apparatus 110 and passes through the internal sample andsheath nozzles (not shown) and cap screws 152.

Referring to FIG. 4B, the particle detection apparatus 110 of FIG. 4A isillustrated from a side cross-sectional view along the plane 4B—4B. Theparticle-laden air flows into the scalper 112 through the inlet 130,where particles that exceed a maximum size limit are removed. The sampleair stream then flows into the concentrator 114 since the scalper 112and concentrator 114 are fluidly contiguous. According to thisembodiment, the concentrator 114 increases the respirable-range particleconcentration and separates out particles smaller than a minimum sizelimit.

The remaining particles in the sample air stream are then delivered tothe sample nozzle 160 which in turn delivers the sample air stream intothe sample sensor compartment 148. The concentrator 114 and the samplesensor compartment 148 are therefore considered to be contiguous and influid communication with each other.

Referring to FIGS. 4C and 4D, the sample air stream flows from theconcentrator 114 into the upper end 162 of the sample nozzle 160. Theflow of the sample air stream through an elongated portion 200 of thesample nozzle 160 is typically laminar. Surrounding the elongatedportion 200 of the sample nozzle 160 is the sheath nozzle 168 which maybe machined into the housing 118. Clean air flow may enter the particledetection apparatus through a flow manifold port 184 that is notrestricted through the presence of a flow manifold plug 190.

The clean air flow then passes through the sheath flow orifice 188. Thesheath flow orifice 188 regulates the volumetric sheath flow rate to adesired value. After the clean air passes through the sheath floworifice 188, it enters into the sheath nozzle 168 which, according tothe embodiment depicted, encompasses the sample nozzle 160. The sheathnozzle 168 has a length sufficient to “straighten” the sheath flow priorto entering the sample sensor compartment 148.

The sheath flow then enters into the sample sensor compartment 1.48along with the particle-laden air sample that is delivered by the samplenozzle 160. The sheath flow helps control the shape of theparticle-laden flow as it exits through the lower end 170 of the samplenozzle 160. The sheath flow also may help prevent optical surfaces frombeing coated with particles from the particle-laden flow.

FIG. 5A illustrates the integrated particle detection apparatus 110 ofFIG. 1 from an alternative side elevation view. Plane 5B—5B extendsthrough the length and depth of the particle detection apparatus 110 andpasses through a flow manifold port (as obscured by a flow manifold plug190) and an internal purge flow orifice and purge flow port (not shown).Plane 5D—5D extends through the width and depth of the particledetection apparatus 110 and passes through an integrated flow manifold(not shown) and flow manifold ports 184 (some of which are obscured byflow manifold plugs 190). Plane 5D—5D also passes through the internalsample and sheath nozzles (not shown).

FIG. 5B represents the particle detection apparatus 110 of FIG. 5A asillustrated from a side cross-sectional view along the plane 5B—5B. Fromthis vantage point a portion of the scalper 112 and the scalper exhaust132 are visible. A portion of the concentrator 114 and the sample sensorcompartment 148 are also in view. The scalper 112, concentrator 114, andsample sensor compartment 148 are all formed in and defined by thehousing 118 of the particle detection apparatus 110.

Referring to FIGS. 5C and 5D, the particle detection apparatus 110includes a flow manifold 202 that is integrated into the apparatushousing 118. Clean air may enter into the integrated flow manifold 202through flow manifold ports 184 that are not obstructed by flow manifoldplugs 190. Purge flow enters the sample sensor compartment 148 byinitially passing through purge flow orifices 186. The purge floworifice 186 may reduce the purge flow rate to a desired value.

After passing through the purge flow orifice 186, the purge flow entersinto purge flow ports 204 that may exist in the housing 118 alongsidethe sheath and sample nozzles 168, 160. Purge flow is typicallyturbulent when it enters the sample sensor compartment 148. Like thesheath flow, the purge flow helps prevent the optics from being coatedwith particles from the particle-laden sample air flow. The resultingmixture of sample, purge and sheath air flow may exit the particledetector apparatus through the sensor exhaust 174.

While specific embodiments and applications have been illustrated anddescribed, it is to be understood that the invention is not limited tothe precise configuration and components disclosed herein. Variousmodifications, changes, and variations which will be apparent to thoseskilled in the art may be made in the arrangement, operation, anddetails of the methods and systems disclosed herein without departingfrom the spirit and scope of the invention.

1. An integrated air stream delivery apparatus suitable for use with asystem for performing analysis based on optical illumination of a sampleair stream, comprising: a scalper portion that separates out particleswithin the sample air stream based on particle size; a concentratorportion that alters a concentration of particles within the sample airstream; and an illumination area that receives the sample air streamfrom the concentrator portion, where the illumination area is configuredto receive illumination from a light source for illuminating the sampleair stream; wherein the scalper portion, concentrator portion andillumination area comprise a single integrated unit and are in fluidcommunication with each other.
 2. The apparatus of claim 1, wherein thescalper portion, concentrator portion and illumination area are definedby a housing.
 3. The apparatus of claim 2, wherein the housing definespassageways through which the sample flows between the scalper portion,concentrator portion and illumination area.
 4. The apparatus of claim 2,wherein the housing comprises two housing portions providing access toan interior of the scalper portion, the concentrator portion and theillumination area.
 5. The apparatus of claim 4, further comprising asealing gasket that provides a seal between the two housing portionswhen they are joined together.
 6. The apparatus of claim 2, furthercomprising a flow manifold having flow passages integrated in thehousing.
 7. The apparatus of claim 2, further comprising a sample nozzlefor delivering the sample air stream to the illumination area.
 8. Theapparatus of claim 7, wherein the sample nozzle has a position withinthe housing that is adjustable from an outside of the housing.
 9. Theapparatus of claim 7, further comprising a sheath nozzle machined intothe housing that is concentric with the sample nozzle.
 10. The apparatusof claim 1, wherein the scalper portion removes particles larger thanabout ten microns in diameter from the sample.
 11. The apparatus ofclaim 1, wherein the concentrator portion increases the concentration ofparticles within the sample and removes particles smaller than about onemicron in diameter from the sample.
 12. The apparatus of claim 1,wherein the illumination area comprises: a chamber; a port for receivinga light source; and a port for receiving an optical detector.
 13. Theapparatus of claim 12, further comprising at least one optical detector.14. The apparatus of claim 13, wherein the at least one optical detectoris a fluorescence detector.
 15. The apparatus of claim 13, wherein theat least one optical detector is at least one of: an elastic scatterdetector, a laser power detector, and an obscuration detector.
 16. Theapparatus of claim 14, wherein the light source is a laser light source.17. The apparatus of claim 14, wherein the light source is a lightemitting diode.
 18. A particle detection apparatus for detectingparticles in a sample air stream, comprising: a scalper configured toseparate out particles within the sample air stream based on particlesize; a concentrator configured to increase a concentration of particlesin the sample air stream; and a sensor configured to detect particles,the sensor being an induced fluorescence sensor system; wherein thescalper is fluidly contiguous with the concentrator and the concentratoris fluidly contiguous with the sensor and wherein the inducedfluorescence sensor system includes a light source, a fluorescencedetector, a light source power detector and an elastic scatter detector.19. The apparatus of claim 18, wherein the light source is a laser-lightsource.
 20. The apparatus of claim 18, wherein the light source is alight emitting diode.
 21. The apparatus of claim 18, wherein the lightsource is adjustable in all directions along a mounting plane.
 22. Theapparatus of claim 18, further comprising a sample nozzle configured todeliver the sample air stream from the concentrator to the sensor. 23.The apparatus of claim 22, wherein the sample nozzle has a positionwithin a housing that is adjustable from an outside of the housing. 24.The apparatus of claim 22, further comprising a sheath nozzle formedwithin the housing concentric with the sample nozzle.
 25. The apparatusof claim 18, wherein the scalper is configured to remove particleslarger than about ten microns in diameter from the sample air stream.26. The apparatus of claim 18, wherein the concentrator is configured toremove particles smaller than about one micron in diameter from thesample air stream.
 27. A particle detection apparatus for detectingparticles in a sample air stream, comprising: a scalper that separatesout particles within the sample air stream that are larger than adefined maximum size limit; a concentrator that increases a number ofparticles by volume in the sample air stream; a sample sensorcompartment where fluorescence of sample particles occurs; a housing;and ports for receiving at least one light source and at least oneoptical detector; wherein the scalper, concentrator and sample sensorcompartment are in fluid communication with each other and are definedby the housing.
 28. The apparatus of claim 27, wherein the concentratorseparates out particles within the sample that are smaller than adefined minimum size limit.
 29. The apparatus of claim 28, wherein themaximum size limit is about 10 microns in diameter and the minimum sizelimit is about 1 micron in diameter.
 30. The apparatus of claim 27,wherein the housing comprises removable pieces providing access to aninterior of the scalper, the concentrator, and the sample sensorcompartment.
 31. The apparatus of claim 30, further comprising a sealingmember that provides a seal between the removable pieces when theremovable pieces are joined together.
 32. The apparatus of claim 27,further comprising a flow manifold having flow passages integrated inthe housing.